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><A
NAME="PLPYTHON-UTIL"
>42.9. Utility Functions</A
></H1
><P
>   The <TT
CLASS="LITERAL"
>plpy</TT
> module also provides the functions
   <TT
CLASS="LITERAL"
>plpy.debug(<TT
CLASS="REPLACEABLE"
><I
>msg</I
></TT
>)</TT
>,
   <TT
CLASS="LITERAL"
>plpy.log(<TT
CLASS="REPLACEABLE"
><I
>msg</I
></TT
>)</TT
>,
   <TT
CLASS="LITERAL"
>plpy.info(<TT
CLASS="REPLACEABLE"
><I
>msg</I
></TT
>)</TT
>,
   <TT
CLASS="LITERAL"
>plpy.notice(<TT
CLASS="REPLACEABLE"
><I
>msg</I
></TT
>)</TT
>,
   <TT
CLASS="LITERAL"
>plpy.warning(<TT
CLASS="REPLACEABLE"
><I
>msg</I
></TT
>)</TT
>,
   <TT
CLASS="LITERAL"
>plpy.error(<TT
CLASS="REPLACEABLE"
><I
>msg</I
></TT
>)</TT
>, and
   <TT
CLASS="LITERAL"
>plpy.fatal(<TT
CLASS="REPLACEABLE"
><I
>msg</I
></TT
>)</TT
>.
   <CODE
CLASS="FUNCTION"
>plpy.error</CODE
> and
   <CODE
CLASS="FUNCTION"
>plpy.fatal</CODE
> actually raise a Python exception
   which, if uncaught, propagates out to the calling query, causing
   the current transaction or subtransaction to be aborted.
   <TT
CLASS="LITERAL"
>raise plpy.Error(<TT
CLASS="REPLACEABLE"
><I
>msg</I
></TT
>)</TT
> and
   <TT
CLASS="LITERAL"
>raise plpy.Fatal(<TT
CLASS="REPLACEABLE"
><I
>msg</I
></TT
>)</TT
> are
   equivalent to calling
   <CODE
CLASS="FUNCTION"
>plpy.error</CODE
> and
   <CODE
CLASS="FUNCTION"
>plpy.fatal</CODE
>, respectively.
   The other functions only generate messages of different
   priority levels.
   Whether messages of a particular priority are reported to the client,
   written to the server log, or both is controlled by the
   <A
HREF="runtime-config-logging.html#GUC-LOG-MIN-MESSAGES"
>log_min_messages</A
> and
   <A
HREF="runtime-config-logging.html#GUC-CLIENT-MIN-MESSAGES"
>client_min_messages</A
> configuration
   variables. See <A
HREF="runtime-config.html"
>Chapter 18</A
> for more information.
  </P
><P
>   Another set of utility functions are
   <TT
CLASS="LITERAL"
>plpy.quote_literal(<TT
CLASS="REPLACEABLE"
><I
>string</I
></TT
>)</TT
>,
   <TT
CLASS="LITERAL"
>plpy.quote_nullable(<TT
CLASS="REPLACEABLE"
><I
>string</I
></TT
>)</TT
>, and
   <TT
CLASS="LITERAL"
>plpy.quote_ident(<TT
CLASS="REPLACEABLE"
><I
>string</I
></TT
>)</TT
>.  They
   are equivalent to the built-in quoting functions described in <A
HREF="functions-string.html"
>Section 9.4</A
>.  They are useful when constructing
   ad-hoc queries.  A PL/Python equivalent of dynamic SQL from <A
HREF="plpgsql-statements.html#PLPGSQL-QUOTE-LITERAL-EXAMPLE"
>Example 39-1</A
> would be:
</P><PRE
CLASS="PROGRAMLISTING"
>plpy.execute("UPDATE tbl SET %s = %s WHERE key = %s" % (
    plpy.quote_ident(colname),
    plpy.quote_nullable(newvalue),
    plpy.quote_literal(keyvalue)))</PRE
><P>
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